1. Field of the Invention
This invention relates generally to a chemical method for embossing a ceramic acoustical product.
2. Description of the Prior Art
A method for making a ceramic acoustical product is disclosed in U.S. Pat. No. 3,371,134-Ollinger. A low-density, light-colored ceramic acoustical board, which is both incombustible and dimensionally stable, is formed by slurrying water, inorganic wool, and a clay having the characteristics of Mississippi M & D clay; forming a water laid sheet from said slurry; and drying and firing the sheet at a temperature in the range of 1000.degree. F. to 1600.degree. F. to form a ceramic bond. Surface texture has been provided to such board products by using conventional punching techniques to open up and form a disrupted surface or by embossing the unfired board prior to firing. Both techniques have been found to adversely affect the overall strength of the board. The mechanical disruption serves to weaken the board and the embossing of the unfired board interferes with the fired strength since it disrupts the intimately felted product and interferes with the ability of the clay particles to form good bonds.
Other methods for forming acoustical tile products having cratered surfaces are also disclosed in U.S. Pat. No. 2,791,020-Heine and U.S. Pat. No. 2,825,420-Heine.